added histograms comparison into opencv_stitching

modules/stitching/autocalib.cpp

@@ -56,7 +56,7 @@ double estimateFocal(const vector<Mat> &images, const vector<ImageFeatures> &/*f
         }
     }
 
-    if (focals.size() >= 2 * (num_images - 1))
+    if (static_cast<int>(focals.size()) >= 2 * (num_images - 1))
     {
         nth_element(focals.begin(), focals.end(), focals.begin() + focals.size()/2);
         return focals[focals.size()/2];

modules/stitching/main.cpp

@@ -26,6 +26,9 @@ void printUsage()
         << "\t[--output <result_img>]\n\n";
     cout << "--matchconf\n"
         << "\tGood values are in [0.2, 0.8] range usually.\n\n";
+    cout << "HINT:\n"  
+        << "\tDefault parameters are for '--trygpu no' configuration.\n"
+        << "\tTry bigger values for --work_megapix if something is wrong.\n\n";
 }
 
 int main(int argc, char* argv[])
@@ -35,15 +38,17 @@ int main(int argc, char* argv[])
 
     vector<string> img_names;
     vector<Mat> images;
-    bool trygpu = true;
-    double work_megapix = 1;
+
+    // Default parameters
+    bool trygpu = false;
+    double work_megapix = 0.2;
     double compose_megapix = 1;
     int ba_space = BundleAdjuster::FOCAL_RAY_SPACE;
     float conf_thresh = 1.f;
     bool wave_correct = true;
     int warp_type = Warper::SPHERICAL;
     bool user_match_conf = false;
-    float match_conf = 0.55f;
+    float match_conf = 0.6f;
     int seam_find_type = SeamFinder::VORONOI;
     int blend_type = Blender::MULTI_BAND;
     string result_name = "result.png";

modules/stitching/matchers.cpp

 #include <algorithm>
 #include <functional>
+#include <opencv2/highgui/highgui.hpp>
 #include <opencv2/calib3d/calib3d.hpp>
 #include <opencv2/gpu/gpu.hpp>
 #include "matchers.hpp"
@@ -9,6 +10,31 @@ using namespace std;
 using namespace cv;
 using namespace cv::gpu;
 
+
+//////////////////////////////////////////////////////////////////////////////
+
+void FeaturesFinder::operator ()(const vector<Mat> &images, vector<ImageFeatures> &features) 
+{ 
+    features.resize(images.size());
+
+    // Calculate histograms
+    for (size_t i = 0; i < images.size(); ++i)
+    {
+        Mat hsv;
+        cvtColor(images[i], hsv, CV_BGR2HSV);
+        int hbins = 30, sbins = 32, vbins = 30;
+        int hist_size[] = { hbins, sbins, vbins };
+        float hranges[] = { 0, 180 };
+        float sranges[] = { 0, 256 };
+        float vranges[] = { 0, 256 };
+        const float* ranges[] = { hranges, sranges, vranges };
+        int channels[] = { 0, 1, 2 };
+        calcHist(&hsv, 1, channels, Mat(), features[i].hist, 3, hist_size, ranges);
+    }
+
+    find(images, features);
+}
+
 //////////////////////////////////////////////////////////////////////////////
 
 namespace
@@ -19,7 +45,7 @@ namespace
         inline CpuSurfFeaturesFinder(double hess_thresh, int num_octaves, int num_layers, 
                                      int num_octaves_descr, int num_layers_descr) 
         {
-            detector_ = new /*FastFeatureDetector;*/SurfFeatureDetector(hess_thresh, num_octaves, num_layers);
+            detector_ = new SurfFeatureDetector(hess_thresh, num_octaves, num_layers);
             extractor_ = new SurfDescriptorExtractor(num_octaves_descr, num_layers_descr);
         }
 
@@ -149,14 +175,32 @@ void FeaturesMatcher::operator ()(const vector<Mat> &images, const vector<ImageF
     for (size_t i = 0; i < images.size(); ++i)
     {
         LOGLN("Processing image " << i << "... ");
-        for (size_t j = 0; j < images.size(); ++j)
+        for (size_t j = i + 1; j < images.size(); ++j)
+        {
+            // Save time by ignoring poor pairs
+            if (compareHist(features[i].hist, features[j].hist, CV_COMP_INTERSECT) 
+                < min(images[i].size().area(), images[j].size().area()) * 0.4)
             {
-            if (i == j)
+                //LOGLN("Ignoring (" << i << ", " << j << ") pair...");
                 continue;
+            }
+
             size_t pair_idx = i * images.size() + j;
+
             (*this)(images[i], features[i], images[j], features[j], pairwise_matches[pair_idx]);
             pairwise_matches[pair_idx].src_img_idx = i;
             pairwise_matches[pair_idx].dst_img_idx = j;
+
+            // Set up dual pair matches info
+            size_t dual_pair_idx = j * images.size() + i;
+            pairwise_matches[dual_pair_idx] = pairwise_matches[pair_idx];
+            pairwise_matches[dual_pair_idx].src_img_idx = j;
+            pairwise_matches[dual_pair_idx].dst_img_idx = i;
+            if (!pairwise_matches[pair_idx].H.empty())
+                pairwise_matches[dual_pair_idx].H = pairwise_matches[pair_idx].H.inv();
+            for (size_t i = 0; i < pairwise_matches[dual_pair_idx].matches.size(); ++i)
+                swap(pairwise_matches[dual_pair_idx].matches[i].queryIdx,
+                     pairwise_matches[dual_pair_idx].matches[i].trainIdx);
         }
     }
 }

modules/stitching/matchers.hpp

@@ -7,6 +7,7 @@
 
 struct ImageFeatures
 {    
+    cv::Mat hist;
     std::vector<cv::KeyPoint> keypoints;
     cv::Mat descriptors;
 };
@@ -16,7 +17,7 @@ class FeaturesFinder
 {
 public:
     virtual ~FeaturesFinder() {}
-    void operator ()(const std::vector<cv::Mat> &images, std::vector<ImageFeatures> &features) { find(images, features); }
+    void operator ()(const std::vector<cv::Mat> &images, std::vector<ImageFeatures> &features);
 
 protected:
     virtual void find(const std::vector<cv::Mat> &images, std::vector<ImageFeatures> &features) = 0;
@@ -26,7 +27,7 @@ protected:
 class SurfFeaturesFinder : public FeaturesFinder
 {
 public:
-    explicit SurfFeaturesFinder(bool try_use_gpu = true, double hess_thresh = 500.0, 
+    SurfFeaturesFinder(bool try_use_gpu = true, double hess_thresh = 300.0, 
                        int num_octaves = 3, int num_layers = 4, 
                        int num_octaves_descr = 4, int num_layers_descr = 2);
 
@@ -70,7 +71,7 @@ protected:
 class BestOf2NearestMatcher : public FeaturesMatcher
 {
 public:
-    explicit BestOf2NearestMatcher(bool try_use_gpu = true, float match_conf = 0.55f, int num_matches_thresh1 = 5, int num_matches_thresh2 = 5);
+    BestOf2NearestMatcher(bool try_use_gpu = true, float match_conf = 0.55f, int num_matches_thresh1 = 6, int num_matches_thresh2 = 6);
 
 protected:
     void match(const cv::Mat &img1, const ImageFeatures &features1, const cv::Mat &img2, const ImageFeatures &features2,

modules/stitching/motion_estimators.cpp

@@ -130,7 +130,7 @@ void BundleAdjuster::estimate(const vector<Mat> &images, const vector<ImageFeatu
         total_num_matches_ += static_cast<int>(pairwise_matches[edges_[i].first * num_images_ + edges_[i].second].num_inliers);
 
     CvLevMarq solver(num_images_ * 4, total_num_matches_ * 3,
-                     cvTermCriteria(CV_TERMCRIT_EPS + CV_TERMCRIT_ITER, 100, DBL_EPSILON));
+                     cvTermCriteria(CV_TERMCRIT_EPS + CV_TERMCRIT_ITER, 1000, DBL_EPSILON));
 
     CvMat matParams = cameras_;
     cvCopy(&matParams, solver.param);
@@ -142,7 +142,7 @@ void BundleAdjuster::estimate(const vector<Mat> &images, const vector<ImageFeatu
         CvMat* _J = 0;
         CvMat* _err = 0;
 
-        bool proceed = solver.update( _param, _J, _err );
+        bool proceed = solver.update(_param, _J, _err);
 
         cvCopy( _param, &matParams );